// SPDX-License-Identifier: GPL-2.0

/*

* gendisk handling

*

* Portions Copyright (C) 2020 Christoph Hellwig

*/

#include <linux/module.h>

#include <linux/ctype.h>

#include <linux/fs.h>

#include <linux/kdev_t.h>

#include <linux/kernel.h>

#include <linux/blkdev.h>

#include <linux/backing-dev.h>

#include <linux/init.h>

#include <linux/spinlock.h>

#include <linux/proc_fs.h>

#include <linux/seq_file.h>

#include <linux/slab.h>

#include <linux/kmod.h>

#include <linux/major.h>

#include <linux/mutex.h>

#include <linux/idr.h>

#include <linux/log2.h>

#include <linux/pm_runtime.h>

#include <linux/badblocks.h>

#include <linux/part_stat.h>

#include <linux/blktrace_api.h>

#include "blk-throttle.h"

#include "blk.h"

#include "blk-mq-sched.h"

#include "blk-rq-qos.h"

#include "blk-cgroup.h"

static struct kobject *block_depr;

/*

* Unique, monotonically increasing sequential number associated with block

* devices instances (i.e. incremented each time a device is attached).

* Associating uevents with block devices in userspace is difficult and racy:

* the uevent netlink socket is lossy, and on slow and overloaded systems has

* a very high latency.

* Block devices do not have exclusive owners in userspace, any process can set

* one up (e.g. loop devices). Moreover, device names can be reused (e.g. loop0

* can be reused again and again).

* A userspace process setting up a block device and watching for its events

* cannot thus reliably tell whether an event relates to the device it just set

* up or another earlier instance with the same name.

* This sequential number allows userspace processes to solve this problem, and

* uniquely associate an uevent to the lifetime to a device.

*/

static atomic64_t diskseq;

/* for extended dynamic devt allocation, currently only one major is used */

#define NR_EXT_DEVT (1 << MINORBITS)

static DEFINE_IDA(ext_devt_ida);

void set_capacity(struct gendisk *disk, sector_t sectors)

{

if (sectors > BLK_DEV_MAX_SECTORS) {

pr_warn_once("%s: truncate capacity from %lld to %lld\n",

disk->disk_name, sectors,

BLK_DEV_MAX_SECTORS);

sectors = BLK_DEV_MAX_SECTORS;

}

bdev_set_nr_sectors(disk->part0, sectors);

}

EXPORT_SYMBOL(set_capacity);

/*

* Set disk capacity and notify if the size is not currently zero and will not

* be set to zero. Returns true if a uevent was sent, otherwise false.

*/

bool set_capacity_and_notify(struct gendisk *disk, sector_t size)

{

sector_t capacity = get_capacity(disk);

char *envp[] = { "RESIZE=1", NULL };

set_capacity(disk, size);

/*

* Only print a message and send a uevent if the gendisk is user visible

* and alive. This avoids spamming the log and udev when setting the

* initial capacity during probing.

*/

if (size == capacity ||

!disk_live(disk) ||

(disk->flags & GENHD_FL_HIDDEN))

return false;

pr_info_ratelimited("%s: detected capacity change from %lld to %lld\n",

disk->disk_name, capacity, size);

/*

* Historically we did not send a uevent for changes to/from an empty

* device.

*/

if (!capacity || !size)

return false;

kobject_uevent_env(&disk_to_dev(disk)->kobj, KOBJ_CHANGE, envp);

return true;

}

EXPORT_SYMBOL_GPL(set_capacity_and_notify);

static void part_stat_read_all(struct block_device *part,

struct disk_stats *stat)

{

int cpu;

memset(stat, 0, sizeof(struct disk_stats));

for_each_possible_cpu(cpu) {

struct disk_stats *ptr = per_cpu_ptr(part->bd_stats, cpu);

int group;

for (group = 0; group < NR_STAT_GROUPS; group++) {

stat->nsecs[group] += ptr->nsecs[group];

stat->sectors[group] += ptr->sectors[group];

stat->ios[group] += ptr->ios[group];

stat->merges[group] += ptr->merges[group];

}

stat->io_ticks += ptr->io_ticks;

}

}

static void bdev_count_inflight_rw(struct block_device *part,

unsigned int inflight[2], bool mq_driver)

{

int write = 0;

int read = 0;

int cpu;

if (mq_driver) {

blk_mq_in_driver_rw(part, inflight);

return;

}

for_each_possible_cpu(cpu) {

read += part_stat_local_read_cpu(part, in_flight[READ], cpu);

write += part_stat_local_read_cpu(part, in_flight[WRITE], cpu);

}

/*

* While iterating all CPUs, some IOs may be issued from a CPU already

* traversed and complete on a CPU that has not yet been traversed,

* causing the inflight number to be negative.

*/

inflight[READ] = read > 0 ? read : 0;

inflight[WRITE] = write > 0 ? write : 0;

}

/**

* bdev_count_inflight - get the number of inflight IOs for a block device.

*

* @part: the block device.

*

* Inflight here means started IO accounting, from bdev_start_io_acct() for

* bio-based block device, and from blk_account_io_start() for rq-based block

* device.

*/

unsigned int bdev_count_inflight(struct block_device *part)

{

unsigned int inflight[2] = {0};

bdev_count_inflight_rw(part, inflight, false);

return inflight[READ] + inflight[WRITE];

}

EXPORT_SYMBOL_GPL(bdev_count_inflight);

/*

* Can be deleted altogether. Later.

*

*/

#define BLKDEV_MAJOR_HASH_SIZE 255

static struct blk_major_name {

struct blk_major_name *next;

int major;

char name[16];

#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD

void (*probe)(dev_t devt);

#endif

} *major_names[BLKDEV_MAJOR_HASH_SIZE];

static DEFINE_MUTEX(major_names_lock);

static DEFINE_SPINLOCK(major_names_spinlock);

/* index in the above - for now: assume no multimajor ranges */

static inline int major_to_index(unsigned major)

{

return major % BLKDEV_MAJOR_HASH_SIZE;

}

#ifdef CONFIG_PROC_FS

void blkdev_show(struct seq_file *seqf, off_t offset)

{

struct blk_major_name *dp;

spin_lock(&major_names_spinlock);

for (dp = major_names[major_to_index(offset)]; dp; dp = dp->next)

if (dp->major == offset)

seq_printf(seqf, "%3d %s\n", dp->major, dp->name);

spin_unlock(&major_names_spinlock);

}

#endif /* CONFIG_PROC_FS */

/**

* __register_blkdev - register a new block device

*

* @major: the requested major device number [1..BLKDEV_MAJOR_MAX-1]. If

* @major = 0, try to allocate any unused major number.

* @name: the name of the new block device as a zero terminated string

* @probe: pre-devtmpfs / pre-udev callback used to create disks when their

* pre-created device node is accessed. When a probe call uses

* add_disk() and it fails the driver must cleanup resources. This

* interface may soon be removed.

*

* The @name must be unique within the system.

*

* The return value depends on the @major input parameter:

*

* - if a major device number was requested in range [1..BLKDEV_MAJOR_MAX-1]

* then the function returns zero on success, or a negative error code

* - if any unused major number was requested with @major = 0 parameter

* then the return value is the allocated major number in range

* [1..BLKDEV_MAJOR_MAX-1] or a negative error code otherwise

*

* See Documentation/admin-guide/devices.txt for the list of allocated

* major numbers.

*

* Use register_blkdev instead for any new code.

*/

int __register_blkdev(unsigned int major, const char *name,

void (*probe)(dev_t devt))

{

struct blk_major_name **n, *p;

int index, ret = 0;

mutex_lock(&major_names_lock);

/* temporary */

if (major == 0) {

for (index = ARRAY_SIZE(major_names)-1; index > 0; index--) {

if (major_names[index] == NULL)

break;

}

if (index == 0) {

printk("%s: failed to get major for %s\n",

__func__, name);

ret = -EBUSY;

goto out;

}

major = index;

ret = major;

}

if (major >= BLKDEV_MAJOR_MAX) {

pr_err("%s: major requested (%u) is greater than the maximum (%u) for %s\n",

__func__, major, BLKDEV_MAJOR_MAX-1, name);

ret = -EINVAL;

goto out;

}

p = kmalloc_obj(struct blk_major_name);

if (p == NULL) {

ret = -ENOMEM;

goto out;

}

p->major = major;

#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD

p->probe = probe;

#endif

strscpy(p->name, name, sizeof(p->name));

p->next = NULL;

index = major_to_index(major);

spin_lock(&major_names_spinlock);

for (n = &major_names[index]; *n; n = &(*n)->next) {

if ((*n)->major == major)

break;

}

if (!*n)

*n = p;

else

ret = -EBUSY;

spin_unlock(&major_names_spinlock);

if (ret < 0) {

printk("register_blkdev: cannot get major %u for %s\n",

major, name);

kfree(p);

}

out:

mutex_unlock(&major_names_lock);

return ret;

}

EXPORT_SYMBOL(__register_blkdev);

void unregister_blkdev(unsigned int major, const char *name)

{

struct blk_major_name **n;

struct blk_major_name *p = NULL;

int index = major_to_index(major);

mutex_lock(&major_names_lock);

spin_lock(&major_names_spinlock);

for (n = &major_names[index]; *n; n = &(*n)->next)

if ((*n)->major == major)

break;

if (!*n || strcmp((*n)->name, name)) {

WARN_ON(1);

} else {

p = *n;

*n = p->next;

}

spin_unlock(&major_names_spinlock);

mutex_unlock(&major_names_lock);

kfree(p);

}

EXPORT_SYMBOL(unregister_blkdev);

int blk_alloc_ext_minor(void)

{

int idx;

idx = ida_alloc_range(&ext_devt_ida, 0, NR_EXT_DEVT - 1, GFP_KERNEL);

if (idx == -ENOSPC)

return -EBUSY;

return idx;

}

void blk_free_ext_minor(unsigned int minor)

{

ida_free(&ext_devt_ida, minor);

}

void disk_uevent(struct gendisk *disk, enum kobject_action action)

{

struct block_device *part;

unsigned long idx;

rcu_read_lock();

xa_for_each(&disk->part_tbl, idx, part) {

if (bdev_is_partition(part) && !bdev_nr_sectors(part))

continue;

if (!kobject_get_unless_zero(&part->bd_device.kobj))

continue;

rcu_read_unlock();

kobject_uevent(bdev_kobj(part), action);

put_device(&part->bd_device);

rcu_read_lock();

}

rcu_read_unlock();

}

EXPORT_SYMBOL_GPL(disk_uevent);

int disk_scan_partitions(struct gendisk *disk, blk_mode_t mode)

{

struct file *file;

int ret = 0;

if (!disk_has_partscan(disk))

return -EINVAL;

if (disk->open_partitions)

return -EBUSY;

/*

* If the device is opened exclusively by current thread already, it's

* safe to scan partitons, otherwise, use bd_prepare_to_claim() to

* synchronize with other exclusive openers and other partition

* scanners.

*/

if (!(mode & BLK_OPEN_EXCL)) {

ret = bd_prepare_to_claim(disk->part0, disk_scan_partitions,

NULL);

if (ret)

return ret;

}

set_bit(GD_NEED_PART_SCAN, &disk->state);

file = bdev_file_open_by_dev(disk_devt(disk), mode & ~BLK_OPEN_EXCL,

NULL, NULL);

if (IS_ERR(file))

ret = PTR_ERR(file);

else

fput(file);

/*

* If blkdev_get_by_dev() failed early, GD_NEED_PART_SCAN is still set,

* and this will cause that re-assemble partitioned raid device will

* creat partition for underlying disk.

*/

clear_bit(GD_NEED_PART_SCAN, &disk->state);

if (!(mode & BLK_OPEN_EXCL))

bd_abort_claiming(disk->part0, disk_scan_partitions);

return ret;

}

static void add_disk_final(struct gendisk *disk)

{

struct device *ddev = disk_to_dev(disk);

if (!(disk->flags & GENHD_FL_HIDDEN)) {

bdev_add(disk->part0, ddev->devt);

if (get_capacity(disk))

disk_scan_partitions(disk, BLK_OPEN_READ);

/*

* Announce the disk and partitions after all partitions are

* created. (for hidden disks uevents remain suppressed forever)

*/

dev_set_uevent_suppress(ddev, 0);

disk_uevent(disk, KOBJ_ADD);

}

blk_apply_bdi_limits(disk->bdi, &disk->queue->limits);

disk_add_events(disk);

set_bit(GD_ADDED, &disk->state);

}

static int __add_disk(struct device *parent, struct gendisk *disk,

const struct attribute_group **groups,

struct fwnode_handle *fwnode)

{

struct device *ddev = disk_to_dev(disk);

int ret;

if (WARN_ON_ONCE(bdev_nr_sectors(disk->part0) > BLK_DEV_MAX_SECTORS))

return -EINVAL;

if (queue_is_mq(disk->queue)) {

/*

* ->submit_bio and ->poll_bio are bypassed for blk-mq drivers.

*/

if (disk->fops->submit_bio || disk->fops->poll_bio)

return -EINVAL;

} else {

if (!disk->fops->submit_bio)

return -EINVAL;

bdev_set_flag(disk->part0, BD_HAS_SUBMIT_BIO);

}

/*

* If the driver provides an explicit major number it also must provide

* the number of minors numbers supported, and those will be used to

* setup the gendisk.

* Otherwise just allocate the device numbers for both the whole device

* and all partitions from the extended dev_t space.

*/

ret = -EINVAL;

if (disk->major) {

if (WARN_ON(!disk->minors))

goto out;

if (disk->minors > DISK_MAX_PARTS) {

pr_err("block: can't allocate more than %d partitions\n",

DISK_MAX_PARTS);

disk->minors = DISK_MAX_PARTS;

}

if (disk->first_minor > MINORMASK ||

disk->minors > MINORMASK + 1 ||

disk->first_minor + disk->minors > MINORMASK + 1)

goto out;

} else {

if (WARN_ON(disk->minors))

goto out;

ret = blk_alloc_ext_minor();

if (ret < 0)

goto out;

disk->major = BLOCK_EXT_MAJOR;

disk->first_minor = ret;

}

/* delay uevents, until we scanned partition table */

dev_set_uevent_suppress(ddev, 1);

ddev->parent = parent;

ddev->groups = groups;

dev_set_name(ddev, "%s", disk->disk_name);

if (fwnode)

device_set_node(ddev, fwnode);

if (!(disk->flags & GENHD_FL_HIDDEN))

ddev->devt = MKDEV(disk->major, disk->first_minor);

ret = device_add(ddev);

if (ret)

goto out_free_ext_minor;

ret = disk_alloc_events(disk);

if (ret)

goto out_device_del;

ret = sysfs_create_link(block_depr, &ddev->kobj,

kobject_name(&ddev->kobj));

if (ret)

goto out_device_del;

/*

* avoid probable deadlock caused by allocating memory with

* GFP_KERNEL in runtime_resume callback of its all ancestor

* devices

*/

pm_runtime_set_memalloc_noio(ddev, true);

disk->part0->bd_holder_dir =

kobject_create_and_add("holders", &ddev->kobj);

if (!disk->part0->bd_holder_dir) {

ret = -ENOMEM;

goto out_del_block_link;

}

disk->slave_dir = kobject_create_and_add("slaves", &ddev->kobj);

if (!disk->slave_dir) {

ret = -ENOMEM;

goto out_put_holder_dir;

}

ret = blk_register_queue(disk);

if (ret)

goto out_put_slave_dir;

if (!(disk->flags & GENHD_FL_HIDDEN)) {

ret = bdi_register(disk->bdi, "%u:%u",

disk->major, disk->first_minor);

if (ret)

goto out_unregister_queue;

bdi_set_owner(disk->bdi, ddev);

ret = sysfs_create_link(&ddev->kobj,

&disk->bdi->dev->kobj, "bdi");

if (ret)

goto out_unregister_bdi;

} else {

/*

* Even if the block_device for a hidden gendisk is not

* registered, it needs to have a valid bd_dev so that the

* freeing of the dynamic major works.

*/

disk->part0->bd_dev = MKDEV(disk->major, disk->first_minor);

}

return 0;

out_unregister_bdi:

if (!(disk->flags & GENHD_FL_HIDDEN))

bdi_unregister(disk->bdi);

out_unregister_queue:

blk_unregister_queue(disk);

rq_qos_exit(disk->queue);

out_put_slave_dir:

kobject_put(disk->slave_dir);

disk->slave_dir = NULL;

out_put_holder_dir:

kobject_put(disk->part0->bd_holder_dir);

out_del_block_link:

sysfs_remove_link(block_depr, dev_name(ddev));

pm_runtime_set_memalloc_noio(ddev, false);

out_device_del:

device_del(ddev);

out_free_ext_minor:

if (disk->major == BLOCK_EXT_MAJOR)

blk_free_ext_minor(disk->first_minor);

out:

return ret;

}

/**

* add_disk_fwnode - add disk information to kernel list with fwnode

* @parent: parent device for the disk

* @disk: per-device partitioning information

* @groups: Additional per-device sysfs groups

* @fwnode: attached disk fwnode

*

* This function registers the partitioning information in @disk

* with the kernel. Also attach a fwnode to the disk device.

*/

int __must_check add_disk_fwnode(struct device *parent, struct gendisk *disk,

const struct attribute_group **groups,

struct fwnode_handle *fwnode)

{

struct blk_mq_tag_set *set;

unsigned int memflags;

int ret;

if (queue_is_mq(disk->queue)) {

set = disk->queue->tag_set;

memflags = memalloc_noio_save();

down_read(&set->update_nr_hwq_lock);

ret = __add_disk(parent, disk, groups, fwnode);

up_read(&set->update_nr_hwq_lock);

memalloc_noio_restore(memflags);

} else {

ret = __add_disk(parent, disk, groups, fwnode);

}

/*

* add_disk_final() needn't to read `nr_hw_queues`, so move it out

* of read lock `set->update_nr_hwq_lock` for avoiding unnecessary

* lock dependency on `disk->open_mutex` from scanning partition.

*/

if (!ret)

add_disk_final(disk);

return ret;

}

EXPORT_SYMBOL_GPL(add_disk_fwnode);

/**

* device_add_disk - add disk information to kernel list

* @parent: parent device for the disk

* @disk: per-device partitioning information

* @groups: Additional per-device sysfs groups

*

* This function registers the partitioning information in @disk

* with the kernel.

*/

int __must_check device_add_disk(struct device *parent, struct gendisk *disk,

const struct attribute_group **groups)

{

return add_disk_fwnode(parent, disk, groups, NULL);

}

EXPORT_SYMBOL(device_add_disk);

static void blk_report_disk_dead(struct gendisk *disk, bool surprise)

{

struct block_device *bdev;

unsigned long idx;

/*

* On surprise disk removal, bdev_mark_dead() may call into file

* systems below. Make it clear that we're expecting to not hold

* disk->open_mutex.

*/

lockdep_assert_not_held(&disk->open_mutex);

rcu_read_lock();

xa_for_each(&disk->part_tbl, idx, bdev) {

if (!kobject_get_unless_zero(&bdev->bd_device.kobj))

continue;

rcu_read_unlock();

bdev_mark_dead(bdev, surprise);

put_device(&bdev->bd_device);

rcu_read_lock();

}

rcu_read_unlock();

}

static bool __blk_mark_disk_dead(struct gendisk *disk)

{

/*

* Fail any new I/O.

*/

if (test_and_set_bit(GD_DEAD, &disk->state))

return false;

if (test_bit(GD_OWNS_QUEUE, &disk->state))

blk_queue_flag_set(QUEUE_FLAG_DYING, disk->queue);

/*

* Stop buffered writers from dirtying pages that can't be written out.

*/

set_capacity(disk, 0);

/*

* Prevent new I/O from crossing bio_queue_enter().

*/

return blk_queue_start_drain(disk->queue);

}

/**

* blk_mark_disk_dead - mark a disk as dead

* @disk: disk to mark as dead

*

* Mark as disk as dead (e.g. surprise removed) and don't accept any new I/O

* to this disk.

*/

void blk_mark_disk_dead(struct gendisk *disk)

{

__blk_mark_disk_dead(disk);

blk_report_disk_dead(disk, true);

}

EXPORT_SYMBOL_GPL(blk_mark_disk_dead);

static void __del_gendisk(struct gendisk *disk)

{

struct request_queue *q = disk->queue;

struct block_device *part;

unsigned long idx;

bool start_drain;

might_sleep();

if (WARN_ON_ONCE(!disk_live(disk) && !(disk->flags & GENHD_FL_HIDDEN)))

return;

disk_del_events(disk);

/*

* Prevent new openers by unlinked the bdev inode.

*/

mutex_lock(&disk->open_mutex);

xa_for_each(&disk->part_tbl, idx, part)

bdev_unhash(part);

mutex_unlock(&disk->open_mutex);

/*

* Tell the file system to write back all dirty data and shut down if

* it hasn't been notified earlier.

*/

if (!test_bit(GD_DEAD, &disk->state))

blk_report_disk_dead(disk, false);

/*

* Drop all partitions now that the disk is marked dead.

*/

mutex_lock(&disk->open_mutex);

start_drain = __blk_mark_disk_dead(disk);

if (start_drain)

blk_freeze_acquire_lock(q);

xa_for_each_start(&disk->part_tbl, idx, part, 1)

drop_partition(part);

mutex_unlock(&disk->open_mutex);

if (!(disk->flags & GENHD_FL_HIDDEN)) {

sysfs_remove_link(&disk_to_dev(disk)->kobj, "bdi");

/*

* Unregister bdi before releasing device numbers (as they can

* get reused and we'd get clashes in sysfs).

*/

bdi_unregister(disk->bdi);

}

blk_unregister_queue(disk);

kobject_put(disk->part0->bd_holder_dir);

kobject_put(disk->slave_dir);

disk->slave_dir = NULL;

part_stat_set_all(disk->part0, 0);

disk->part0->bd_stamp = 0;

sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk)));

pm_runtime_set_memalloc_noio(disk_to_dev(disk), false);

device_del(disk_to_dev(disk));

blk_mq_freeze_queue_wait(q);

blk_throtl_cancel_bios(disk);

blk_sync_queue(q);

blk_flush_integrity();

if (queue_is_mq(q))

blk_mq_cancel_work_sync(q);

rq_qos_exit(q);

/*

* If the disk does not own the queue, allow using passthrough requests

* again. Else leave the queue frozen to fail all I/O.

*/

if (!test_bit(GD_OWNS_QUEUE, &disk->state))

__blk_mq_unfreeze_queue(q, true);

else if (queue_is_mq(q))

blk_mq_exit_queue(q);

if (start_drain)

blk_unfreeze_release_lock(q);

}

static void disable_elv_switch(struct request_queue *q)

{

struct blk_mq_tag_set *set = q->tag_set;

WARN_ON_ONCE(!queue_is_mq(q));

down_write(&set->update_nr_hwq_lock);

blk_queue_flag_set(QUEUE_FLAG_NO_ELV_SWITCH, q);

up_write(&set->update_nr_hwq_lock);

}

/**

* del_gendisk - remove the gendisk

* @disk: the struct gendisk to remove

*

* Removes the gendisk and all its associated resources. This deletes the

* partitions associated with the gendisk, and unregisters the associated

* request_queue.

*

* This is the counter to the respective device_add_disk() call.

*

* The final removal of the struct gendisk happens when its refcount reaches 0

* with put_disk(), which should be called after del_gendisk(), if

* device_add_disk() was used.

*

* Drivers exist which depend on the release of the gendisk to be synchronous,

* it should not be deferred.

*

* Context: can sleep

*/

void del_gendisk(struct gendisk *disk)

{

struct blk_mq_tag_set *set;

unsigned int memflags;

if (!queue_is_mq(disk->queue)) {

__del_gendisk(disk);

} else {

set = disk->queue->tag_set;

disable_elv_switch(disk->queue);

memflags = memalloc_noio_save();

down_read(&set->update_nr_hwq_lock);

__del_gendisk(disk);

up_read(&set->update_nr_hwq_lock);

memalloc_noio_restore(memflags);

}

}

EXPORT_SYMBOL(del_gendisk);

/**

* invalidate_disk - invalidate the disk

* @disk: the struct gendisk to invalidate

*

* A helper to invalidates the disk. It will clean the disk's associated

* buffer/page caches and reset its internal states so that the disk

* can be reused by the drivers.

*

* Context: can sleep

*/

void invalidate_disk(struct gendisk *disk)

{

struct block_device *bdev = disk->part0;

invalidate_bdev(bdev);

bdev->bd_mapping->wb_err = 0;

set_capacity(disk, 0);

}

EXPORT_SYMBOL(invalidate_disk);

/* sysfs access to bad-blocks list. */

static ssize_t disk_badblocks_show(struct device *dev,

struct device_attribute *attr,

char *page)

{

struct gendisk *disk = dev_to_disk(dev);

if (!disk->bb)

return sysfs_emit(page, "\n");

return badblocks_show(disk->bb, page, 0);

}

static ssize_t disk_badblocks_store(struct device *dev,

struct device_attribute *attr,

const char *page, size_t len)

{

struct gendisk *disk = dev_to_disk(dev);

if (!disk->bb)

return -ENXIO;

return badblocks_store(disk->bb, page, len, 0);

}

#ifdef CONFIG_BLOCK_LEGACY_AUTOLOAD

static bool blk_probe_dev(dev_t devt)

{

unsigned int major = MAJOR(devt);

struct blk_major_name **n;

mutex_lock(&major_names_lock);

for (n = &major_names[major_to_index(major)]; *n; n = &(*n)->next) {

if ((*n)->major == major && (*n)->probe) {

(*n)->probe(devt);

mutex_unlock(&major_names_lock);

return true;

}

}

mutex_unlock(&major_names_lock);

return false;

}

void blk_request_module(dev_t devt)

{

int error;

if (blk_probe_dev(devt))

return;

error = request_module("block-major-%d-%d", MAJOR(devt), MINOR(devt));

/* Make old-style 2.4 aliases work */

if (error > 0)

error = request_module("block-major-%d", MAJOR(devt));

if (!error)

blk_probe_dev(devt);

}

#endif /* CONFIG_BLOCK_LEGACY_AUTOLOAD */

#ifdef CONFIG_PROC_FS

/* iterator */

static void *disk_seqf_start(struct seq_file *seqf, loff_t *pos)

{

loff_t skip = *pos;

struct class_dev_iter *iter;

struct device *dev;

iter = kmalloc_obj(*iter);

if (!iter)

return ERR_PTR(-ENOMEM);

seqf->private = iter;

class_dev_iter_init(iter, &block_class, NULL, &disk_type);

do {

dev = class_dev_iter_next(iter);

if (!dev)

return NULL;

} while (skip--);

return dev_to_disk(dev);

}

static void *disk_seqf_next(struct seq_file *seqf, void *v, loff_t *pos)

{

struct device *dev;

(*pos)++;

dev = class_dev_iter_next(seqf->private);

if (dev)

return dev_to_disk(dev);

return NULL;

}

static void disk_seqf_stop(struct seq_file *seqf, void *v)

{

struct class_dev_iter *iter = seqf->private;

/* stop is called even after start failed :-( */

if (iter) {

class_dev_iter_exit(iter);

kfree(iter);

seqf->private = NULL;

}

}

static void *show_partition_start(struct seq_file *seqf, loff_t *pos)

{

void *p;

p = disk_seqf_start(seqf, pos);

if (!IS_ERR_OR_NULL(p) && !*pos)

seq_puts(seqf, "major minor #blocks name\n\n");

return p;

}

static int show_partition(struct seq_file *seqf, void *v)

{

struct gendisk *sgp = v;

struct block_device *part;

unsigned long idx;

if (!get_capacity(sgp) || (sgp->flags & GENHD_FL_HIDDEN))

return 0;

rcu_read_lock();

xa_for_each(&sgp->part_tbl, idx, part) {

if (!bdev_nr_sectors(part))

continue;

seq_printf(seqf, "%4d %7d %10llu %pg\n",

MAJOR(part->bd_dev), MINOR(part->bd_dev),

bdev_nr_sectors(part) >> 1, part);

}

rcu_read_unlock();

return 0;

}

static const struct seq_operations partitions_op = {

.start = show_partition_start,

.next = disk_seqf_next,

.stop = disk_seqf_stop,

.show = show_partition

};

#endif

static int __init genhd_device_init(void)

{

int error;

error = class_register(&block_class);

if (unlikely(error))

return error;

blk_dev_init();

register_blkdev(BLOCK_EXT_MAJOR, "blkext");